Nonskid rubber sole construction



June 26, 1951 I D E, CR OKER 2,557,946

Patented June 26, 1951 UNITED STATES PATENT OFFICE I 2,557,946 7 NONSKID RUBBER SOLE CONSTRUCTION David E. Crooker, Ontonagon, Mich assignor of one-half to Lloyd L. Felker, Marshfield, Wis.

Application February 18, 1948, Serial No. 9,279

4-Claims. 1

This invention relates to improvements in nonskid rubber sole construction.

In localities where the winters are relatively cold and the populace must contend with icy streets, sidewalks and the like. it is desirable to have footwear which will provide adequate traction on ice as well as on other slippery surfaces, thereby preventing costly and painful accidents. In addition to footwear worn by the general public, there are special applications wherein a non-skid sole is particularly desirable. Some of these are: lumbermens footwear, hunters boots, railroad workers shoes, and fishe'rmens wading boots. Heretofore, no non-skid sole has been developed which has proved entirely satisfactory in all of the above applications.

It is therefore a general object of the present invention to provide a sole for footwear which will elfectively grip slippery surfaces such as those covered with ice and thereby provide adequate traction and insure the safety of the wearer.

A further object of the invention is to provide a non-skid rubber sole which will not interfere with the normal flexing of the article of footwear during use.

A further object of the invention is to provide a non-skid rubber sole which is relatively easy to attach and which has exceptional wearing qualities.

A more specific object of the invention is to provide a non-skid rubber sole formed with transverse ribs having wire coils embedded therein.

A further object of the invention is to provide a non-skid rubber sole which is simple and easy to manufacture, which is applicable during original manufacture of footwear or during a resoling operation, and which is otherwise well adapted for the purposes described.

With the above and other objects in view, the invention consists of the improved non-skid sole construction, and all of its parts and combinations, as set forth in the claims, and all equivalents thereof.

In the accompanying drawing, illustrating one complete embodiment of the preferred form of the invention, in which the same reference numerals designate the same parts in all of the views:

Fig. 1 is a plan view of the bottom of the improved sole;

Fig. 2 is a fragmentary side view thereof;

Fig. 3 is an enlarged fragmentary transverse vertical sectional view taken along the line 3-3 of Fig. 1;

Fig. 4 is an enlarged fragmentary longitudinal vertical sectional View taken along the line 4--4 of Fig. 3;

Fig. 5 is an enlarged fragmentary side view of a modified form of coil which may be used in the improved sole;

Fig. 6 is an enlarged end view of the coil shown in Fig. 5;

Fig. '7 is an enlarged fragmentary side view of a second modified form of coil which may also be used in the improved sole; and

Fig. 3 is an enlarged end view of the in Fig. 7.

Referring more particularly to the drawing, the numeral It indicates a sole of rubber, synthetic rubber, or other material, having rubber-like characteristics, of a size and shape suitable for attachment to a selected article of footwear. The sole I9 is provided with a flat inner surface H, and on its outer surface is formed with transverse ribs l2 spaced apart by transverse grooves l3. The ribs l2 have a rounded outer surface contour as at M (see Fig. 4). Extending longitudinally, preferably within each of the transverse ribs I2, is a helical coil IS. The coil I5 has an outside radius of curvature which is preferably slightly less than the radius of curvature of the rounded portion M of the ribs I2. The coil I5 is preferably so positioned within the rib 12 that a side portion of the coil 15 is substantially flush with the outer rounded surface l4 thereof as at I6 (see Figs. 2 and 4) In the preferred form of the invention shown in Figs. 3 and 4, a two strand twisted wire coil is used, the double strand twisted wire forming irregularities which interlock with the rubber to prevent displacement of the coil during wear. Other forms of wire which may also be used for the coil l5 are a single round strand formed of corrugated wire as shown in Figs. 5 and 6, or a single, twisted strand which is a concave-sided triangle in cross-section, as shown in Figs. 7 and 8.

When one of the improved soles described hereinbefore is put into use, the outer portions [4 of the ribs l2 immediately become subject to wear. This wear quickly exposes the outer portions of the coils l5 at the points 16 and thereby provides a multiplicity of road gripping elements exposed along the wearing surfaces of the ribs l 2.

With continued use, the rounded surfaces ll of the ribs 12 and the portions of the coil l5 therein wear to a substantially fiat outer surface, and portions of the coil I5 which originally projected into the rounded portions of the rib I2 wear away, leaving four wire ends exposed in coil shown place of each of the worn-away elements. The

improved sole will then present a maximum number of traction augmenting elements and, in this condition, possesses maximum non-skid eiflciency.

It will be noted that by the novel arrangement of the coils l5 and the transverse ribs I2, a sole is provided which readily adapts itself to the normal flexing of the footwear while in use, without causing deformation of the coil as a result of said flexing. This feature provides greater comfort for the wearer and prevents breakage of the coils because of said flexing which takes place during use.

While the invention as illustrated is particiilarly adapted for use on the complete sole and heel area, it is obvious that it rnay be applied to the heel portion only or to selected portions of the sole portion only. I

Various changes and modifications and other adaptations may be made without departing from the spirit of the invention, and all of such changes and adaptations are contemplated, as may come within the scope of the claims.

What I claim is:

1. In a sole adapted for attachment to footwear, a flexible rubber tread provided with a plurality of transversely extending spaced ribs, metal coils embedded in said ribs and extending longitudinally thereof, the width of a rib being at least equal to the width of a coil, and each coil having at least its major portion confined in a rib with a side flush with the wearing surface of its rib.

2. In a sole adapted for attachment to footwear, a flexible rubber tread provided with a plurality of transversely extending spaced ribs, metal coils embedded in said ribs and extending longitudinally thereof, the width of a rib being at least equal to the width of a coil, and each coil having at least its major portion confined in a rib with a side flush with the wearing surface of its rib, the convolutions of the coils having ir- 4 regularities which interlock with the rubber to prevent displacement of the coil during use.

3. In a sole adapted for attachment to footwear, a flexible rubber tread provided with a plurality of transversely extending spaced ribs, metal coils embedded in said ribs and extending longitudinally thereof, the width of a rib being at least equal to the width of a coil, and each coil having at least its major portion confined in a rib with a side flush with the wearing surface of its rib, each coil being formed of two twisted together strands and the rubber of the sole interlooking with the twisted strands to prevent displacement of the coils during use.

4; In a sole adapted for attachment to footwear, a flexible rubber tread provided with a plurality of transversely extending spaced ribs, metal coils embedded in said ribs and extending longitudinally thereof, the width of a rib being at least equalto the width of a coil, and each coil having at least its major portion confined in a rib with a side flush withthe wearing surface of its rib, the coils being formed of wire having a plurality of concave sides in cross-section and said wire being axially twisted in addition to being in coil form. 7

DAVID E. CROOKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 322,224 Watkinson July 14, 1885 922,555 Baddock May 25, 1909 1,027,255 Kempshall May 21, 1912 1,199,902 Kempshall Oct. 3, 1916 FOREIGN PATENTS Number Country Date 13,573 Great Britain Mar. 25, 1 915 14,068 Sweden Apr. 19, 1902 

